One seat, Virginia, he ranks as almost a dead-lock certain flip from Republican to Democratic:

Democrats are enthusiastic about their nominee, ex-Gov. Mark Warner, and Republicans are not enthusiastic about their nominee, former Gov. Jim Gilmore, who was formally anointed this weekend by the barest of majorities. National GOPers don’t intend to put money into the race, and they don’t even pretend that it’s going to be competitive.

Ambinder’s analysis seems spot on, especially when you consider the fact that everysinglepollsofar has shown Mark Warner with a near 20 point lead over Gilmore. Moreover, the fact that national Republicans (the NRSC ?) have already written the seat off as a loss bodes ill for down-ticket races in the state as well.

Ambinder goes on to list three states — New Hampshire, New Mexico, and Colorado where he sees at least a 50% chance that the seat will change from Republican to Democratic control —, four states where the seat is currently held by a Republican that he describes as competitive — Alaska, Minnesota, Oregon, and Mississippi — which he describes as “very competitive”, and only one state where there’s at least a 25% chance of a Republican pickup, Louisiana.

Ambinder’s comment on Mississippi are particularly interesting:

MISSISSIPPI — Three recent polls have showed the race between Republican Roger Wicker and Democrat Ronnie Musgrove within the margin of error; black turnout will be huge if Obama is the nominee; no party on the ballot b/c it’s a special election. Still, Wicker has lots of money now and Musgrove has little.

Meanwhile, Ambinder lists three states he describes as marginal; North Carolina, Kentucky, and Maine. Of those three, I think Elizabeth Dole’s seat in the Tarheel State could be the most vulnerable if Obama is able to do well there on Election Day.

So what does this mean ?

The Democrats will pick up the seat in Virginia, and may pick up two of the three 50% states, but I also think we’re likely to see them pick up Mississippi and North Carolina depending on how well Obama does in putting a dent in the GOP’s formerly solid grip on the South.